The present invention relates to surgical retractors and devices for stabilizing a predetermined area of the body during a surgical procedure, more particularly to a stabilizer used in connection with a retractor that is preferably used in coronary artery bypass grafting surgical procedures, and more specifically to a cooled stabilizer attached to a rigid or flexible arm for providing a chilled stabilization surface in contact with body tissue.
Diseases of the cardiovascular system affect millions of people each year and are a cause of death for large numbers of people in the United States and throughout the world. A particularly prevalent form of cardiovascular disease involves a reduction in the blood supply to the heart caused by atherosclerosis (coronary artery disease) or other conditions that create a restriction in blood flow at a critical point in the cardiovascular system affecting blood flow to the heart.
One technique for treating such a blockage or restriction is a surgical procedure known as a coronary artery bypass graft (CABG) procedure, which is commonly performed while using a heart-lung machine (xe2x80x9con-pumpxe2x80x9d), but can also be performed without the heart-lung machine (xe2x80x9coff-pumpxe2x80x9d). The surgical correction of occluded or stenosed coronary arteries by means of bypass grafting is among the most common procedures performed today, especially when multiple grafts are needed.
In the coronary artery bypass graft procedure, the surgeon either removes a portion of a vein or artery from another part of the body for grafting or detaches one end of a local artery, e.g., the left internal mammary artery (LIMA) or the right internal mammary artery (RIMA), and connects that end past the obstruction in the coronary artery while leaving the other end attached to the arterial supply. When using a vein or artery from another part of the body, the surgeon provides arterial supply from the aorta and connects to a point that bypasses the obstruction. In both cases, the objective is to bypass the obstruction and restore normal blood flow to the heart.
In addition, when using the on-pump CABG technique, the surgeon makes a long incision down the middle of the chest, saws through the sternum, spreads the two halves of the sternum apart and then performs the necessary procedures to connect the surgical patient to a cardiopulmonary bypass machine to continue the circulation of oxygenated blood to the rest of the body while the heart is stopped and the graft is being sewn in place. Although such a procedure is one common technique for treatment, the procedure is lengthy, traumatic, costly and can damage the heart, the central nervous system, and the blood supply.
Interventional techniques, such as percutaneous transluminal angioplasty (PTCA), have gained popularity as an alternative method of therapy for atherosclerosis. PTCA is a minimally invasive technique that subjects the patient to reduced trauma and reduced recovery time, especially when compared to on-pump CABG techniques.
Although PTCA procedures are often successful, complications can arise, such as restenosis or thrombosis and embolism. Restenosed vessels often require surgical intervention for correction. The surgical correction of restenosis, like the conventional coronary bypass surgical procedure, previously required the heart to be stopped and the patient placed on heart/lung bypass.
In recent years, and in an effort to reduce cost, risk, and trauma to the patient, physicians have turned to minimally or less invasive surgical approaches to the heart bypass procedure, such as intercostal and endoscopic access to the surgical site. With such off-pump CABG procedures, the heart is beating during the surgical procedure. Thus, there is no need for any form of cardiopulmonary bypass, and there is no need to perform the extensive surgical procedures necessary to connect the patient to such a bypass machine.
Such attempts at performing minimally invasive bypass grafting on a beating heart, however, have been characterized as tedious, dangerous and difficult because of the delicate nature of the surgical procedure, the lack of adequate access to the coronary vessels, and the lack of an ability to adequately stabilize and reduce tissue movement at the graft site. Because these procedures are performed while the heart continues to beat, the blood continues flowing and the heart continues moving in three-dimensional movement while the surgeon attempts to sew the graft in place.
There is disclosed in U.S. Pat. No. 6,348,036 to Looney et al. a surgical retractor and a tissue stabilization device for locally stabilizing a predetermined area of the body. The retractor includes a rail system having two arms and a rack segment interconnecting the two arms for maintaining a desired spacing therebetween. A stabilization arm having a handle segment connects the retractor with the stabilization device. The handle segment is attachable to the retractor by a connector such as a mounting mechanism or a sled member. The stabilization device is pivotally retained at a distal end of the stabilization arm. A bottom surface of the stabilization device can include a textured surface to facilitate engagement with tissue at the predetermined area.
There also is disclosed in U.S. Pat. No. 6,102,854 to Cartier et al. a sternal retractor including a rack bar and two arms attached to rails, and an arm mounted on the rails. A xe2x80x9ccontacting meansxe2x80x9d or stabilizer includes two parallel contacting arms that define an area where a targeted artery is engaged between the arms. Silastic tapes can be wrapped around the targeted artery, thereby restricting blood flow in the arterial window.
There also is disclosed in U.S. Pat. No. 5,730,757 an access platform for the dissection of an internal mammary artery. The described access platform has first and second blades interconnected to a spreader member that laterally drives the blades apart or together, and support pads interconnected to the first blade. A torsional member is operably interconnected to the first blade and the spreader member, and is used to vertically displace the first blade in either direction, thus increasing the surgeon""s working space and visual access for dissection of the internal mammary artery. A tissue retractor interconnected to the blades is used to draw the soft tissue around the incision away from the surgeon""s work area. It is further provided that the access platform can include a port that can be used to mount a heart stabilizer instrument.
There also is described in U.S. Pat. No. 6,306,085 granted to Farascioni; U.S. Pat. No. 6,036,641 to Taylor et al.; U.S. Pat. No. 5,875,782 granted to Ferrari et al.; U.S. Pat. No. 6,033,362 granted to Cohn; U.S. Pat. No. 6,102,854 granted to Cartier et al.; U.S. Pat. No. 5,894,843 granted to Benetti et al.; European Application EP 0 993 806; PCT Publication WO 01/17437; PCT Publication WO 00/62680; and PCT Publication WO 01/58361 various devices for stabilizing a predetermined area on the heart or other organ of a patient, e.g., to enable a surgical procedure on the beating heart. Some of these devices include a stabilizer attached to an elongated arm, which can be movably attached to a rib retractor so that a person is not required to hold the arm. However, none of these devices disclose a chilled surface in contact with the heart for providing traction and quiescence, and that are capable of inducing hemostasis in a targeted area of tissue.
One example of a device for cooling the heart is U.S. Pat. No. 5,117,822 to Laghi, which discloses a spoon-like device including a handle part and a cradling part. The cradling part conforms to the shape of the human heart and serves to separate the heart from the walls of the thoracic cavity. Chilled saline solution is pumped through a passageway in the handle and seeps out through perforations onto the heart itself. Most of the saline solution forms a puddle in the thoracic cavity and is aspirated by a vacuum manifold.
Another example of a device for cooling the heart is provided in U.S. Pat. No. 5,799,661 to Boyd et al., which discloses a topical hypothermia device (see FIGS. 42-47) including a flexible heat exchanger with a passage for circulating cooling fluid. In use, the heat exchanger is filled with fluid and placed against the heart in contact with the myocardium. A pump forces cooling fluid from an outside reservoir into the device and through the passage of the heat exchanger. The reservoir can be cooled by an ice bath to provide cooling fluid of 0-4xc2x0 C.
However, the prior art does not disclose a device that provides for traction, quiescence, or is capable of inducing hemostasis on a targeted area of the heart adjacent a grafting site. Further, none of these prior art devices are configured to be attached to an elongated arm for use with a surgical retractor.
It is therefore desirable to provide a cooled stabilizer device and system for providing traction and quiescence, and that can be capable of inducing hemostasis in a predetermined area of an organ such as the heart, and methods for using such a device.
The present invention features a system for retracting, manipulating, and stabilizing a predetermined area of the body. The system includes a stabilizer device having a chilled surface which provides traction and quiescence, and that can be capable of inducing hemostasis in a localized area of an organ such as the heart, and methods of use related thereto.
The cooled stabilizer and related devices and apparatuses that are featured herein are particularly advantageous for use in performing off-pump coronary artery bypass grafting (CABG) procedures in which the heart remains beating during the surgical procedure and/or other surgery in which the heart is stopped. One advantage of the present invention relates to the versatile use of the cooled stabilizer which is connected to an elongated arm and any location along the arms of a retractor or a rack portion thereof, and which can be manipulated to a desired position over an organ such as the heart. Additionally, the arm with cooled stabilizer of the present invention allows for a full range of three-dimensional motion which is controlled by a single knob that is spaced apart from each of the retractor and the arm. The cooled stabilizer is pivotable on an end of the arm by a ball-and-socket or other known joint.
The general shape of the cooled stabilizer can resemble devices of the type commonly known as the Cohn Cardiac Stabilizer or the Immobilizer marketed by the Genzyme Corporation of Cambridge, Mass. The preferred form of the stabilizer is a generally horseshoe shaped member having a planar surface with a centrally located opening therein that may or may not include a removable end piece thereon. Other suitable forms include square, rectangular, or teardrop shaped members. The central opening or window area is an area through which the surgeon performs the anastomosis or other procedure on the tissue of the beating heart. One form of the stabilizer is a multiple piece member so that once the anastomosis is completed, the pieces or an end portion thereof may be separated to remove the device from around the anastomosis.
Optionally, flexible tapes such as silastic tapes can be sutured through the tissue and then threaded around and connected to the stabilizer to provide temporary vessel occlusion by capturing the tissue and adjacent blood vessel against the bottom surface of the stabilizer. Once the stabilizer is positioned in the desired orientation and location in contact with the tissue, the flexible tapes are then pulled snug through the opening of the stabilizer to provide localized stabilization through both compression and traction forces on the artery or tissue.
A cooled stabilizer according to the present invention can include an insulated upper surface and a thermally conductive bottom surface having one or more channels, the channels circulating a fluid, preferably a cooling fluid to provide traction and quiescence to the adjacent tissue, and being capable of inducing localized hemostasis on a targeted area of body tissue and/or an artery. As used herein, the term xe2x80x9cchannelxe2x80x9d refers to, for example, a line, a conduit, a tube, or space formed within the stabilizer that is capable of transmitting fluid along a path.
The cooled stabilizer includes one or more members, preferably two members, surrounding the targeted area adjacent a graft site. The bottom surface or a portion thereof of each of the members can be a thermally conductive surface for transferring the effects of the cooled fluid in contact with the targeted area on an organ, e.g., the heart.
The channels can be formed in one or more loops and include at least one inlet and one outlet, the inlet and outlet preferably elevated above the upper surface of the stabilizer. A preferred form of the stabilizer is in the shape of a horseshoe, with a thermally conductive surface provided on the bottom surface of the two members, or horseshoe sections of the horseshoe, and optionally including a heel being either a conductive surface or an insulating surface. If desired, the heel can be omitted and a differently shaped stabilizer can be provided, such as one having two or more parallel members. In any of these designs, it is desired to provide sufficient contact surface to cool the tissue adjacent to the targeted area to thereby reduce movement of the tissue.
The channels preferably are made integral with the bottom surface of the stabilizer. For example, the channels or tubes can be welded to the bottom surface. Alternatively, the tubes can be formed within plates having outer surfaces which serve as the upper and bottom surfaces of the stabilizer. The bottom surfaces in the heel and horseshoe sections preferably are made of biocompatible materials or surface treated with biocompatible materials. The tubes can circulate cooling fluid having a temperature of between approximately xe2x88x9230xc2x0 C. and 10xc2x0 C., or more preferably approximately xe2x88x9220xc2x0 C. and 0xc2x0 C., and still more preferably approximately xe2x88x9210xc2x0 C. to 0xc2x0 C.
In one example of the present invention, the channels are positioned around a periphery of the bottom surface of the stabilizer members (i.e. horseshoe sections) for distributing cooling fluid over a large area thereof. In another example, the bottom surface of the horseshoe sections can be a thermally conductive surface formed with one or more pads for providing traction and having an approximately constant temperature distribution over the surface of the pads. The pads can be positioned directly over the channels or can encompass a larger surface area, e.g., covering substantially the entire bottom surface of the horseshoe sections. In yet another example, the channels can be milled into plates for circulating fluid through the plates.
In a horseshoe configuration, the heel can include a flat bottom surface continuous with the bottom surface of the horseshoe sections, or alternatively can include a depressed or a raised portion, depending on whether minimized compression or additional compression, respectively, is to be imparted to the coronary artery and body tissue therearound.
In a further example of the cooled stabilizer of the present invention, a plurality of members can be arranged approximately parallel to each other around a targeted area of the epicardium. A surgeon can operate in a window of reduced movement tissue located between the members. Preferably the members include thermally conductive bottom surfaces and upper surfaces that can be conductive or insulative, the upper surfaces being linked together by a connecting member.
Other aspects and examples of the invention are more fully discussed below.